Combined effects of UVC waterproof LED and slightly acidic electrolyzed water (SAEW) on the reduction of bacterial pathogens risk in fresh cabbage and mung bean sprouts

Abstract

This study investigated the combined effects of washing with slightly acidic electrolyzed water (SAEW; 30 ppm) and ultraviolet-C waterproof light emitting diodes (UVC W-LED; 275 nm) on Salmonella spp. and Listeria monocytogenes numbers in fresh-cut shredded cabbage and mung bean sprouts. The risk reduction effect of washing was also evaluated by quantitative microbial risk assessment (QMRA) using @Risk. The combined treatment when used for 5 min, effectively decreased the contamination levels of hygiene indicator microorganisms, Salmonella spp., and L. monocytogenes in shredded cabbage (1.13–1.44 log CFU/g) and mung bean sprouts (1.45–1.64 log CFU/g). Neither pathogen survived in SAEW + UVC W-LED. The contamination levels of both pathogens increased from market to home, but L. monocytogenes grew more slowly than Salmonella spp. in cabbage and mung bean sprouts. Washing lowered the average probability risk of both pathogens in cabbage (Salmonella; 1.05 × 10−1, Listeria; 3.16 x 10−5) and mung bean sprouts (Salmonella; 6.62 × 10−2, Listeria; 1.25 × 10−7). The probability risk of salmonellosis and listeriosis was higher in cabbage than in mung bean sprouts, and the probability of listeriosis risk increased 10 times for the susceptible population. Transportation time from market to home is the most influential factor in increasing the risk of both pathogens in cabbage and mung bean sprouts. The synergistic effect of UVC W-LED with SAEW for washing fresh vegetables can be expected to decrease contamination levels and prevent cross-contamination during washing processing.